aboutsummaryrefslogtreecommitdiff
path: root/pkg/autoupdate/autoupdate.go
blob: 7c243eb00162d74e1eaffd4107108073920f15cf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
package autoupdate

import (
	"context"
	"os"
	"sort"

	"github.com/containers/image/v5/docker"
	"github.com/containers/image/v5/docker/reference"
	"github.com/containers/image/v5/manifest"
	"github.com/containers/image/v5/transports/alltransports"
	"github.com/containers/libpod/libpod"
	"github.com/containers/libpod/libpod/define"
	"github.com/containers/libpod/libpod/image"
	"github.com/containers/libpod/pkg/systemd"
	systemdGen "github.com/containers/libpod/pkg/systemd/generate"
	"github.com/containers/libpod/pkg/util"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

// Label denotes the container/pod label key to specify auto-update policies in
// container labels.
const Label = "io.containers.autoupdate"

// Policy represents an auto-update policy.
type Policy string

const (
	// PolicyDefault is the default policy denoting no auto updates.
	PolicyDefault Policy = "disabled"
	// PolicyNewImage is the policy to update as soon as there's a new image found.
	PolicyNewImage = "image"
)

// Map for easy lookups of supported policies.
var supportedPolicies = map[string]Policy{
	"":         PolicyDefault,
	"disabled": PolicyDefault,
	"image":    PolicyNewImage,
}

// LookupPolicy looksup the corresponding Policy for the specified
// string. If none is found, an errors is returned including the list of
// supported policies.
//
// Note that an empty string resolved to PolicyDefault.
func LookupPolicy(s string) (Policy, error) {
	policy, exists := supportedPolicies[s]
	if exists {
		return policy, nil
	}

	// Sort the keys first as maps are non-deterministic.
	keys := []string{}
	for k := range supportedPolicies {
		if k != "" {
			keys = append(keys, k)
		}
	}
	sort.Strings(keys)

	return "", errors.Errorf("invalid auto-update policy %q: valid policies are %+q", s, keys)
}

// ValidateImageReference checks if the specified imageName is a fully-qualified
// image reference to the docker transport (without digest).  Such a reference
// includes a domain, name and tag (e.g., quay.io/podman/stable:latest).  The
// reference may also be prefixed with "docker://" explicitly indicating that
// it's a reference to the docker transport.
func ValidateImageReference(imageName string) error {
	// Make sure the input image is a docker.
	imageRef, err := alltransports.ParseImageName(imageName)
	if err == nil && imageRef.Transport().Name() != docker.Transport.Name() {
		return errors.Errorf("auto updates require the docker image transport but image is of transport %q", imageRef.Transport().Name())
	} else if err != nil {
		repo, err := reference.Parse(imageName)
		if err != nil {
			return errors.Wrap(err, "error enforcing fully-qualified docker transport reference for auto updates")
		}
		if _, ok := repo.(reference.NamedTagged); !ok {
			return errors.Errorf("auto updates require fully-qualified image references (no tag): %q", imageName)
		}
		if _, ok := repo.(reference.Digested); ok {
			return errors.Errorf("auto updates require fully-qualified image references without digest: %q", imageName)
		}
	}
	return nil
}

// AutoUpdate looks up containers with a specified auto-update policy and acts
// accordingly.  If the policy is set to PolicyNewImage, it checks if the image
// on the remote registry is different than the local one. If the image digests
// differ, it pulls the remote image and restarts the systemd unit running the
// container.
//
// It returns a slice of successfully restarted systemd units and a slice of
// errors encountered during auto update.
func AutoUpdate(runtime *libpod.Runtime) ([]string, []error) {
	// Create a map from `image ID -> []*Container`.
	containerMap, errs := imageContainersMap(runtime)
	if len(containerMap) == 0 {
		return nil, errs
	}

	// Create a map from `image ID -> *image.Image` for image lookups.
	imagesSlice, err := runtime.ImageRuntime().GetImages()
	if err != nil {
		return nil, []error{err}
	}
	imageMap := make(map[string]*image.Image)
	for i := range imagesSlice {
		imageMap[imagesSlice[i].ID()] = imagesSlice[i]
	}

	// Connect to DBUS.
	conn, err := systemd.ConnectToDBUS()
	if err != nil {
		logrus.Errorf(err.Error())
		return nil, []error{err}
	}
	defer conn.Close()

	// Update images.
	containersToRestart := []*libpod.Container{}
	updatedRawImages := make(map[string]bool)
	for imageID, containers := range containerMap {
		image, exists := imageMap[imageID]
		if !exists {
			errs = append(errs, errors.Errorf("container image ID %q not found in local storage", imageID))
			return nil, errs
		}
		// Now we have to check if the image of any containers must be updated.
		// Note that the image ID is NOT enough for this check as a given image
		// may have multiple tags.
		for i, ctr := range containers {
			rawImageName := ctr.RawImageName()
			if rawImageName == "" {
				errs = append(errs, errors.Errorf("error auto-updating container %q: raw-image name is empty", ctr.ID()))
			}
			needsUpdate, err := newerImageAvailable(runtime, image, rawImageName)
			if err != nil {
				errs = append(errs, errors.Wrapf(err, "error auto-updating container %q: image check for %q failed", ctr.ID(), rawImageName))
				continue
			}
			if !needsUpdate {
				continue
			}
			logrus.Infof("Auto-updating container %q using image %q", ctr.ID(), rawImageName)
			if _, updated := updatedRawImages[rawImageName]; !updated {
				_, err = updateImage(runtime, rawImageName)
				if err != nil {
					errs = append(errs, errors.Wrapf(err, "error auto-updating container %q: image update for %q failed", ctr.ID(), rawImageName))
					continue
				}
				updatedRawImages[rawImageName] = true
			}
			containersToRestart = append(containersToRestart, containers[i])
		}
	}

	// Restart containers.
	updatedUnits := []string{}
	for _, ctr := range containersToRestart {
		labels := ctr.Labels()
		unit, exists := labels[systemdGen.EnvVariable]
		if !exists {
			// Shouldn't happen but let's be sure of it.
			errs = append(errs, errors.Errorf("error auto-updating container %q: no %s label found", ctr.ID(), systemdGen.EnvVariable))
			continue
		}
		_, err := conn.RestartUnit(unit, "replace", nil)
		if err != nil {
			errs = append(errs, errors.Wrapf(err, "error auto-updating container %q: restarting systemd unit %q failed", ctr.ID(), unit))
			continue
		}
		logrus.Infof("Successfully restarted systemd unit %q", unit)
		updatedUnits = append(updatedUnits, unit)
	}

	return updatedUnits, errs
}

// imageContainersMap generates a map[image ID] -> [containers using the image]
// of all containers with a valid auto-update policy.
func imageContainersMap(runtime *libpod.Runtime) (map[string][]*libpod.Container, []error) {
	allContainers, err := runtime.GetAllContainers()
	if err != nil {
		return nil, []error{err}
	}

	errors := []error{}
	imageMap := make(map[string][]*libpod.Container)
	for i, ctr := range allContainers {
		state, err := ctr.State()
		if err != nil {
			errors = append(errors, err)
			continue
		}
		// Only update running containers.
		if state != define.ContainerStateRunning {
			continue
		}
		// Only update containers with the specific label/policy set.
		labels := ctr.Labels()
		if value, exists := labels[Label]; exists {
			policy, err := LookupPolicy(value)
			if err != nil {
				errors = append(errors, err)
				continue
			}
			if policy != PolicyNewImage {
				continue
			}
		}
		// Now we know that `ctr` is configured for auto updates.
		id, _ := ctr.Image()
		imageMap[id] = append(imageMap[id], allContainers[i])
	}

	return imageMap, errors
}

// newerImageAvailable returns true if there corresponding image on the remote
// registry is newer.
func newerImageAvailable(runtime *libpod.Runtime, img *image.Image, origName string) (bool, error) {
	remoteRef, err := docker.ParseReference("//" + origName)
	if err != nil {
		return false, err
	}

	remoteImg, err := remoteRef.NewImage(context.Background(), runtime.SystemContext())
	if err != nil {
		return false, err
	}

	rawManifest, _, err := remoteImg.Manifest(context.Background())
	if err != nil {
		return false, err
	}

	remoteDigest, err := manifest.Digest(rawManifest)
	if err != nil {
		return false, err
	}

	return img.Digest().String() != remoteDigest.String(), nil
}

// updateImage pulls the specified image.
func updateImage(runtime *libpod.Runtime, name string) (*image.Image, error) {
	sys := runtime.SystemContext()
	registryOpts := image.DockerRegistryOptions{}
	signaturePolicyPath := ""
	authFilePath := ""

	if sys != nil {
		registryOpts.OSChoice = sys.OSChoice
		registryOpts.ArchitectureChoice = sys.OSChoice
		registryOpts.DockerCertPath = sys.DockerCertPath

		signaturePolicyPath = sys.SignaturePolicyPath
		authFilePath = sys.AuthFilePath
	}

	newImage, err := runtime.ImageRuntime().New(context.Background(),
		docker.Transport.Name()+"://"+name,
		signaturePolicyPath,
		authFilePath,
		os.Stderr,
		&registryOpts,
		image.SigningOptions{},
		nil,
		util.PullImageAlways,
	)
	if err != nil {
		return nil, err
	}
	return newImage, nil
}